Syringe with detachable syringe barrel

ABSTRACT

The syringe ( 10 ) comprises a detachable syringe barrel ( 14 ) connected to a housing ( 12 ). The housing contains a drive means connected to a plunger ( 24 ). The drive means is for extending and retracting the plunger into and out of the detachable syringe barrel. The detachable syringe barrel comprises a stopper ( 26 ) at one end thereof in sealing engagement with the interior of the barrel and for releasable engagement with the end of the plunger distal to the drive means. At least a portion of the stopper is flexible between a first position and a second position. In the first position, the flexible stopper may be disengaged from the plunger upon retraction of the plunger away from the detachable syringe barrel. In the second position, the flexible stopper is maybe engaged with the plunger upon extension of the plunger toward the detachable syringe barrel.

TECHNICAL FIELD

In one of its aspect, the present invention relates to a syringe with adetachable syringe barrel. In another of its aspects, the presentinvention relates to a detachable syringe barrel for use in a syringe.

BACKGROUND ART

Syringes are will known in the art. Initial syringes were manuallyoperated instruments comprising needles and syringe barrels. After thebiocompatible liquid (i.e., drug or other liquid) is dispensed or asample is taken with these manually operated instruments, the entireinstrument including the needle, syringe and plunger is discarded (i.e.,the entire instrument is disposable).

Conventional manual syringes, as used in dentistry applications, usuallycomprise a hollow cylindrical housing having one end adapted to receivea needle and the other end adapted to receive a piston assembly. Theouter surface of the housing is provided with a pair of finger gripssuch that the device can be held firmly between the middle and indexfingers of the practitioner's hand. Anaesthetic is commonly supplied inpremeasured ampoules which are designed to fit into the housing. Theampoule has one end provided with a pierceable membrane that receivesthe needle in sealing engagement and another end fitted with a slidableplunger which engages the piston assembly. The piston assembly includesa shaft, one end of which is fitted with a plunger, and an opposing endprovided with a thumb rest. In operation, the anaesthetic injection isadministered by depressing the plunger with the practitioner's thumbwhich causes the piston to engage the plunger, thereby forcinganaesthetic from the ampoule via the needle.

There are several disadvantages associated with conventional manualsyringes used in dentistry applications. For example, due to uneventhumb pressure applied on the thumb rest, the practitioner has verylittle control over the flow rate of anaesthetic exiting the needle. Asa result it is virtually impossible to achieve a substantially constantflow rate with a manual syringe. Further, many practitioners oftencomplain that, due to the manner by which a conventional manual syringeis grasped, such a syringe offers poor control of the needle tip whenadministering the injection. As a result, unsteady injections causeunnecessary pain and discomfort to the patient. Still further, it isgenerally uncontested that the majority of patients dislike the thoughtof receiving an injection, especially a dental injection. Indeed, thisaversion is usually due to the fact that many manual syringes are highlyintimidating in appearance.

Thus, a body of prior art developed relating to electronic syringes. Forexample, U.S. Pat. No. 5,690,618 (Smith et al.), the contents of whichare hereby incorporated by reference, describes an electronic syringewhich is a pen-style grip electronic syringe which allows a practitionerto administer injections or aspirations at a controlled rate and with aprecised degree of hand control. The electronic syringe described inSmith et al. comprises an ampoule receiving first portion wherein anampoule, premanufactured to contain the biocompatible material ofinterest, is placed in this first portion of the syringe foradministration to the patient. After use, the ampoule is simplydiscarded.

While the electronic syringe taught by Smith et al. represents asignificant advance in the art, there is still room for improvement.Specifically, while electronic syringes have overcome some of thedifficulties encountered with manually operated instruments, theseelectronic syringes are limited to use with a premanufactured ampoulecontaining the biocompatible liquid of interest. This leads to a numberof disadvantages.

First, medical personnel using these electronic syringes do not have theability to dispense the biocompatible liquid from a bulk storage supply(e.g., a premanufactured bottle of the biocompatible liquid). This leadsto a significant cost penalty since the medical personnel must purchasea significant number of premanufactured ampoules to equal the numberdosages which could be obtained from bulk storage supply.

Second, the premanufactured ampoules used in conventional syringes aredisadvantageous since they must be discarded after use. From anenvironmental standpoint, this is especially disadvantageous since theampoules tend to be made of glass, rubber and other unrelated materials.

Third, since there is no standard in electronic syringes and/or theampoules used therein, a medical practitioner may be in the predicamentof having the desired biocompatible liquid available only in an ampouledesign which is incompatible with the electronic syringes used by thepractitioner.

Accordingly, it would be desirable to provide a syringe device iscapable of being used: (i) to withdraw biocompatible liquid from a bulksupply, and (ii) thereafter to administer to a patient a predeterminedquantity of the biocompatible liquid. Furthermore, it is desirable toprovide a syringe device which has a detachable syringe barrel which canbe disposed of or sterilized separately from the device, minimizing thesterilization requirements for the instrument between patients. Stillfurther, it would be desirable to have a syringe barrel capable ofsimple detachment from the syringe. Still further, it would be desirableif that syringe could be electronically operated.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a syringe whichobviates or mitigates at least one of the foregoing disadvantages of theprior art.

Accordingly, in one of its aspects, the present invention provides asyringe comprising:

an outer housing comprising drive means connect to a plunger, the drivemeans operable to extend and retract the plunger, and

a detachable syringe barrel connected to the outer housing, thedetachable syringe barrel comprising a stopper at one end thereof insealing engagement with an interior of the barrel and for releasableengagement with an end of the plunger distal to the drive means,

at least a portion of the stopper being flexible between: (i) a firstposition in which the stopper may be disengaged from the plunger uponretraction of the plunger away from the detachable syringe barrel, and(ii) a second position in which the flexible stopper may be engaged withthe plunger upon extension of the plunger toward the detachable syringebarrel.

Thus, the present inventor has developed a novel syringe which obviatesor mitigates at least one of the foregoing disadvantages of the priorart. The present syringe comprises a detachable syringe barrel connectedto a housing. The housing contains a drive means connected to a plunger.The drive means is for extending and retracting the plunger into and outof the detachable syringe barrel. The detachable syringe barrelcomprises a stopper at one end thereof in sealing engagement with theinterior of the barrel and for releasable engagement with the end of theplunger distal to the drive means. At least a portion of the stopper isflexible between a first position and a second position. In the firstposition, the flexible stopper may be disengaged from the plunger uponretraction of the plunger away from the detachable syringe barrel. Inthe second position, the flexible stopper may be engaged with theplunger upon extension of the plunger toward the detachable syringebarrel. In this manner, the end of the plunger distal to the drive meansis releasably engageable with the a portion of the detachable syringebarrel.

In operation, the medical practitioner, actuates the drive means whichextends the plunger. As the plunger is extended into the detachablesyringe barrel the plunger pushes the flexible stopper from its firstposition to its second position. In its second position the flexiblestopper engages the plunger. The plunger is further extend until theflexible stopper abuts the other end of the detachable syringe barrel.At this point, a needle attached to the detachable syringe barrel isdisposed in a bulk supply of biocompatible liquid, the direction of thedrive means is reversed and the drive means is actuated therebyretracting the engaged plunger/flexible stopper to fill the detachablesyringe to the desired level (i.e., prior to flexible stopper reachingthe first position). The syringe may then be used to administer thebiocompatible liquid, for example as described in Smith et al.Thereafter, the plunger is retracted to an extent such the stopperadopts the second position thereby allowing the plunger to be disengagedtherefrom. The detachable syringe barrel may then be detached from thehousing.

In another of its aspects, the present invention provides a syringebarrel for use with a syringe housing, the detachable syringe barrelcomprising:

a stopper at one end thereof in sealing engagement with an interior ofthe barrel and for releasable engagement with an end of a plunger in thesyringe housing;

at least a portion of the stopper being flexible between: (i) a firstposition in which the stopper may be disengaged from the plunger uponretraction of the plunger away from the detachable syringe barrel, and(ii) a second position in which the flexible stopper may be engaged withhe plunger upon extension of the plunger toward the detachable syringebarrel.

In one embodiment, the detachable syringe barrel may be adapted toattach to and detach from the syringe housing—this embodiment will bediscussed in more detail hereinbelow. In another embodiment, however, itis possible that the syringe barrel may be in the form of an ampoule foruse in a device such as the one described in U.S. Pat. No. 5,690,618(Smith et al.), incorporated by reference hereinabove. In this latterembodiment, the end of the housing opposite the stopper preferablycomprises a membrane which may be pierced an end of the needle of thesyringe. Thus, for those practitioners who insist on using ampoules, thepresent syringe barrel may be used advantages to avoid unintentionaldisassembly of the barrel by removal of the stopper near the plunger.

In a preferred embodiment, the flexible stopper comprises an outwardlyprojecting rim and when the flexible stopper is in the first positionthe outwardly projecting rim expands into the internal diameter at therearward end disengaging the plunger. When the flexible stopper is inthe second position, at the frontward end of the detachable syringebarrel, the outwardly projecting rim of the flexible stopper iscompressed inwardly engaging the plunger.

In a further aspect of the present invention there is provided a syringewherein the plunger comprises an outer wall comprising one or moreridges on the outer wall wherein the outward projecting rim iscompressed inwardly around the one or more ridges when the flexiblestopper engages the plunger in the second position.

In a further aspect of the present invention there is provided a syringewherein the detachable syringe barrel further comprises a lockattachment for attaching said detachable syringe to said outer housing.In a preferred embodiment, the lock attachment is a twist lockattachment.

In a further aspect of the present invention, there is provided adetachable syringe barrel with a detachable needle. In a preferredembodiment the needle is disposable. In a further preferred embodimentthe detachable syringe barrel can be attached to the outer housing ofthe syringe in a number of different ways to direct the bevel of theneedle as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described with reference tothe accompanying drawings, wherein like number designate like parts andin which:

FIG. 1 illustrates a perspective view of a first embodiment of thesyringe of the present invention;

FIG. 2 illustrates a partial longitudinal sectional view a firstembodiment of the syringe of the present invention illustrated in FIG.1;

FIG. 3 illustrates a longitudinal sectional view of the flexible stopperin the first position with the disengaged plunger of the syringe of thepresent invention illustrated in FIG. 1;

FIG. 4 illustrates a longitudinal sectional view of the flexible stopperand the plunger as the plunger is being extended into the flexiblestopper causing the flexible stopper to engage the plunger of thesyringe of the present invention illustrated in FIG. 1;

FIG. 5 illustrates a longitudinal sectional view of the flexible stopperin the second position with the engaged plunger of the syringe of thepresent invention illustrated in FIG. 1;

FIG. 6 illustrates a partial longitudinal sectional view of a secondembodiment of the syringe of the present invention;

FIG. 7 illustrates an exploded view of the plunger, syringe barrel anddetachable needle of the second embodiment of the present invention asillustrated in FIG. 2;

FIG. 8 illustrates a perspective view of the needle in a first positionof the second embodiment of the syringe of the present invention asillustrated in FIG. 2;

FIG. 9 illustrates a perspective view of the needle in a second positionof the second embodiment of the syringe of the present invention asillustrated in FIG. 2; and

FIG. 10 illustrates a partial longitudinal sectional view of a thirdembodiment of the syringe of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be more particularly described with referenceto the preferred embodiments illustrated in the following Figures whichdepict an electronic syringe particularly adapted for use in dentalapplications. It is to be understood, however, that the presentinvention may be embodied in a manual syringe or in a syringe (manual orelectronic) adapted for non-dental applications.

Referring to FIG. 1, the syringe 10 comprises an outer housing 12 and adetachable syringe barrel 14. Syringe 10 is an electronic syringe whichis attached to a power supply with extension 16. A needle 18 is attachedto the detachable syringe barrel 14 and syringe 10 has actuating buttons20 and 22 for actuating a drive means (not shown) in the outer housing12 to extend and retract the plunger, respectively.

Referring to FIG. 2, plunger 24 is situated in outer housing 12 andengages the flexible stopper 26 in the detachable syringe barrel 14. Thedetachable syringe barrel 14 has a rearward end 28, a frontward end 30and an outer wall 32. The outer wall 32 defines an internal diameter 34of the detachable syringe barrel 14. The rearward end 28 of thedetachable syringe barrel 24 has an internal diameter 34 which isgreater than the internal diameter 34 of the frontward end 30 of thedetachable syringe barrel 24.

The flexible stopper 26 has an outwardly projecting rim 36. Preferably,the flexible stopper 26 is of a sufficient length so that the flexiblestopper 26 is not ripped or twisted when plunger 24 engages saidflexible stopper 26. In a preferred embodiment, the flexible stopper 26is a rubber stopper.

As shown in FIG. 2, plunger 24 has an outer wall 38 with an outer ridge40 and extends forward and retracts backward when drive means (notshown) in the outer housing 12 are actuated.

Referring to FIGS. 3-5, the actuation of plunger 24 in outer housing 12with the flexible stopper 26 in the detachable syringe barrel 14 isshown. In FIG. 3, the flexible stopper 26 is shown in the firstposition, disengaged from the plunger 24 and the detachable syringebarrel 14 is detached from the outer housing 12. When the plunger 24 isdisengaged from the flexible stopper 26, the outwardly projecting rim 36expands into the larger diameter 34 of the rearward end 28 of thedetachable syringe barrel 14 releasing the outer ridge 40 of the plunger24 and hence the plunger 24 itself from the flexible stopper 26.

Referring to FIGS. 4 and 5, the second position of the flexible stopper26 is shown. The detachable syringe barrel 14 is attached to the outerhousing 12 and as the plunger 24 is extended into the flexible stopper26 it pushes the flexible stopper 26 forward causing the outwardprojecting rim 36 of the flexible stopper 26 to engage the plunger 24 bycompressing inwardly against the plunger 24 and around the outwardlyprojecting rim 36. In this manner the plunger can be extended to thefrontward end 30 of the detachable syringe barrel 14. Likewise, theplunger 24 can be retracted together with the engaged flexible stopperto the rearward end 28 of the detachable syringe barrel 14. In thismanner, the flexible stopper 26 remains engaged with the plunger 24while the plunger travels forwards and backwards in the detachablesyringe 14. However, the plunger 24 is disengaged from the flexiblestopper 26 in the second position to permit the detachable syringebarrel 14 to be detached from the outer housing 12. The detachablesyringe barrel 14 can be a disposable barrel or it can be a reusablebarrel in which case the barrel will have to be sterilized between uses.

Accordingly, to operate the syringe 10 as shown in FIGS. 4 and 5, thedrive means (not shown) in the outer housing 12 is actuated bydepressing actuating button 20 causing the plunger 24 to extend forwardinto the detachable syringe barrel 14 engaging the flexible stopper 14.The plunger 24 is retracted by depressing actuating button 22. At theend of the retraction stroke, the plunger 24 is disengaged from theflexible stopper 26 when the outwardly projecting rim 40 of the flexiblestopper 26 expands into the larger internal diameter 34 at the rearwardend 28 of the detachable syringe barrel 14. By the extension andretraction of the plunger 24 into the detachable syringe barrel 14,medication can be taken up into the detachable syringe barrel 14 andthen administered to the patient.

In a preferred embodiment, there will be a master switch (not shown)which will be placed on the outer housing 12. The master switch willhave two settings: a load mode; and a program mode. When the masterswitch is on the lode mode and the operator pushes the actuating button20 the plunger 24 will extend into the detachable syringe barrel 14rapidly engaging the flexible stopper 26 as the plunger 24 extends tothe frontward end of the detachable syringe barrel 14. The operator canthen push the actuating button 22 and the plunger 24 and flexiblestopper 26 will retract sucking the fluid into the syringe. In theprogram mode, the operator starts to inject the needle and pushes theactuating button 20 extending the plunger into the detachably syringebarrel 14 and engaging the flexible stopper 26 causing the medication orfluid to be expelled initially at a slower pre-set speed so that thereis finer control over the amount of medication or fluid initiallyadministered. The operator can press the actuating button 22 to stop theexpulsion of medication or fluid at any time. In this manner, thissyringe, will be particularly useful in dental applications such asfreezing. When the tissues around the teeth are frozen by injectionusing this syringe, the operator can quickly insert the freezingmedication at one site, stop the administration, and move the needle toa different site repeating the cycle until the desired freezing effectis obtained.

In the second embodiment of the syringe shown in FIG. 6, the needle 18is detachable. At the base of the needle 18 is attached a base portion42 which has a internally threaded hollow core 44. The detachablesyringe barrel 14 has an outer threaded projection 46. The outerthreaded projection 46 is in threaded engagement with the internallythreaded hollow core 44 thereby attaching the needle 18 to thedetachable barrel 14.

Referring to FIG. 7, there is illustrated the detachable needle 18 andthe detachable syringe barrel 14 with a twist lock adjustment 48. Thetwist lock adjustment 48 has two lugs 50 that are approximately 180degrees apart from each other on the detachable syringe barrel 14. Theouter housing 12 has four openings 52 that arc approximately 90 degreesapart on the outer housing 12. The two lugs 50 can be inserted in any ofthe two opposing openings 52 and then by twisting the detachable syringebarrel 14 relative to the outer housing 12 the detachable syringe barrel14 is attached to the outer housing 12. A bevel 54 of needle 18 can bepositioned in a desired direction depending on which two openings 52 theoperator choses to use to lock the detachable syringe barrel 14 to theouter housing 12, as illustrated in FIGS. 8 and 9. Alternatively, baseportion can be designed such that needled 18 may be freely rotated(i.e., through 360°) after attachment to syringe barrel 14.

With reference to FIG. 10, there is illustrated an embodiment of how thepresent syringe barrel may be engaged to housing 12. Specifically, aspring 60 (or other spacer, solid or otherwise—not shown) is disposed atthe bottom of a cavity 62 which forms part of housing 12. Thus, spring60 contracts when plunger 24 is retract into housing 12 and spring 60expands when plunger 24 is extended into syringe barrel 14. This actionof spring 12 serves to compensate for industry variance in carpulelength between different manufacturers.

The syringe 10 described above is an electronic syringe. However, it iscontemplated that the above described syringe 10 and the detachablesyringe barrel 14 could be used with a mechanical, pneumatic or batterycharged syringe device. In particular, the drive means in the outerhousing 12 for extending and retracting the plunger 24 could be a numberof available systems including a motor, pneumatic cylinders, solenoid,electromagnetic or hydraulic systems.

The syringe 10 could be used for administering medications, vitamins,minerals, imaging dyes or the like or for withdrawing fluids from atarget organ—i.e., syringe 10 may be used in virtually any applicationin which a conventional syringe is currently used.

The above description of the preferred embodiments of the presentinvention are in no way intended to limit the scope of the invention asset out in the appended claims hereto.

What is claimed is:
 1. A syringe comprising: an outer housing comprisingdrive means connected to a reusable plunger, the drive means operable toextend and retract the plunger, and a detachable syringe barrelconnected to the outer housing, the detachable syringe barrel comprisinga stopper disposed within the barrel adjacent one end thereof in sealingengagement with an interior of the barrel and for releasable engagementwith an end of the plunger distal to the drive means, at least a portionof the stopper being flexible between: (i) a first position in which thestopper may be disengaged from the plunger upon retraction of theplunger away from the detachable syringe barrel, and (ii) a secondposition in which the flexible stopper may be engaged with the plungerat a point proximal the distal end of the syringe barrel upon extensionof the plunger toward the detachable syringe barrel.
 2. The syringedefined in claim 1, wherein an end of the detachable syringe barrelproximal the outer housing has a larger internal diameter than anopposite end of the detachable syringe barrel.
 3. The syringe defined inclaim 2, wherein the stopper in the first position expands into thelarger internal diameter.
 4. The syringe defined in claim 3, wherein thestopper compressed inwardly engaging the plunger at points along thedetachable syringe barrel distal to the larger internal diameter.
 5. Thesyringe defined in claim 4, wherein the stopper comprises an outwardprojecting rim which expands into the internal diameter at the rearwardend disengaging the plunger.
 6. The syringe defined in claim 5, whereinthe plunger comprises an outer wall comprising one or more ridges on theouter wall wherein the outward projecting rim is compressed inwardlyaround the one or more ridges when the flexible stopper engages theplunger.
 7. The syringe defined in claim 6, wherein the detachablesyringe barrel further comprises a lock attachment for attaching thedetachable syringe to the outer housing.
 8. The syringe defined in claim7, wherein the lock attachment is a twist lock attachment.
 9. Thesyringe defined in any one of claims 1-8, wherein the detachable syringebarrel is disposable.
 10. The syringe defined in any one of claims 1-8,wherein the syringe is an electronic syringe.
 11. The syringe defined inany one of claims 1-8, wherein the syringe further comprises a needlewhich is detachable from the detachable syringe barrel and the needle isdisposable.
 12. The syringe defined in claim 11, wherein the needle isin threaded engagement with the detachable syringe barrel.
 13. A syringebarrel for use with a syringe housing, the syringe barrel comprising: astopper disposed within the barrel adjacent one end thereof in sealingengagement with an interior of the barrel and for releasable engagementwith an end of a reusable plunger in the syringe housing; at least aportion of the stopper being flexible between: (i) a first position inwhich the stopper may be disengaged from the plunger upon retraction ofthe plunger away from the syringe barrel, and (ii) a second position inwhich the flexible stopper may be engaged with the plunger at a pointproximal the distal end of the syringe barrel upon extension of theplunger toward the syringe barrel.
 14. The syringe barrel defined inclaim 13, wherein the barrel is detachable from the syringe housing. 15.The syringe barrel defined in claim 14, wherein an end of the syringebarrel proximal the outer housing has a larger internal diameter than anopposite end of the syringe barrel.
 16. The syringe barrel defined inclaim 15, wherein the stopper in the first position expands into thelarger internal diameter.
 17. The syringe barrel defined in claim 16,wherein the stopper comprises an outward projecting rim which expandsinto the internal diameter at the rearward end disengaging a plunger inthe syringe housing.
 18. The syringe barrel defined in any one of claim13-17, wherein the syringe barrel is disposable.
 19. The syringe barreldefined in any one of claims 13-17, wherein an end of the syringe barrelopposite the stopper comprises a membrane in sealing engagement with thesyringe barrel.
 20. The syringe barrel defined in any one of claims13-17, wherein the syringe barrel further comprises a lock attachmentfor attaching the detachable barrel to the syringe housing.
 21. Thesyringe barrel defined in claim 20, wherein the lock attachment is atwist lock attachment.
 22. The syringe barrel defined in any one ofclaims 13-17, wherein the syringe barrel further comprises a needlewhich is detachable from the syringe barrel.
 23. The syringe barreldefined in claim 22, wherein the needle is in threaded engagement withthe detachable syringe barrel.
 24. The syringe barrel defined in any oneof claims 13-17, wherein the syringe barrel is in the form of anampoule.
 25. The syringe barrel defined in claim 24, wherein the ampoulecontains a biocompatible liquid.